(function (doc, win){
	var docEl = doc.documentElement,
	resizeEvt = 'orientationchange' in window ? 'orientationchange' : 'resize',
	recalc = function () {
	var clientWidth = docEl.clientWidth;

		clientWidth=clientWidth>540?540:clientWidth;
	if (!clientWidth) return;
	docEl.style.fontSize = 100 * (clientWidth / 375) + 'px';
	};
	
	
	if (!doc.addEventListener) return;
	win.addEventListener(resizeEvt, recalc, false);
	doc.addEventListener('DOMContentLoaded', recalc, false);
})(document, window);